Rolf-Martin Mantel writes: [...]

Also, according to the Germany entry and to my vague memory, Germany introduced DST in 1980 rather than 1981, which put pressure on all the small ES countries to come to some kind of harmonisation.

That's correct. I have here a paper from the PTB (Physikalisch-Technische Bundesanstalt, Braunschweig - the responsible "time authority" for Germany) which states: 1980: Apr. 6 to Sept. 28 (!!) 1981: Mar. 29 to Sept. 27 ... Bernard Sieloff U of Saarbruecken, Germany